Time resolved study of femtosecond microfabrication in silica glass

Hiroaki Misawa, Saulius Juodkazis, Andrius Marcinkevičius, Mitsuru Watanabe, Vygantas Mizeikis, Shigeki Matsuo

Research output: Contribution to journalConference article

2 Citations (Scopus)

Abstract

We report investigation of light-induced damage threshold (LIDT) in purified silica (transmission band down to 160 nm) by 350 fs laser pulses at the wavelength of 795 nm and 498 nm. Focusing a single pulse by a high numeric aperture NA = 1.35 microscope objective lens results in one of the lowest single-shot bulk LIDT values reported so far, 5 J/cm2, while the surface ablation threshold is 2.5J/cm2 with both values being well below the critical self-focusing power in silica. Furthermore, we report the peculiarities of damage by two-pulse irradiation (duration of each pulse is 440 fs), where both pulses have energies at the level of 0.5 × LIDT. Comparison between the experimental data and numeric simulation, which takes into account optical free-carrier generation and relaxation, demonstrates that these processes can explain the measured self-focusing, super-continuum generation, and lightinduced damage threshold values. We argue that use of high numeric aperture objective, despite substantial temporal pulse stretching, results in tight focusing which is capable of overcoming the beam self-focusing, and the resulting fabrication quality is comparable to that obtained using shorter pulses.

Original languageEnglish
Pages (from-to)98-109
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume4274
DOIs
Publication statusPublished - 2001 Jun 29
EventLaser Applications in Microelectronic and Optoelectronic Manufacturing VI 2001 - San Jose, United States
Duration: 2001 Jan 202001 Jan 26

Keywords

  • Laser microfabrication
  • Light-induced damage threshold
  • Silica

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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